You feel annoyed when something disturbs you or is against your wishes1. For example, when a mosquito is buzzing around your head all night, when you cannot find the coffee because someone put it in the wrong place, or when a colleague stops by your desk and keeps talking to you when you are working on a deadline. The source of annoyance can be disturbing a number of things: your peace and quiet (e.g., the mosquito), your concentration (e.g., people talking when you are trying to work), your comfort (e.g., a very uncomfortable airplane seat), or your flow of activities (e.g., the misplaced coffee).
Unlike other anger-like emotions, annoyance is a bit volatile: it can change depending on your current mood or activities, and even on the time of day. For instance, the same talkative colleague may be a welcome guest when you have little work to do. What you get genuinely angry about, on the other hand, is relatively static.
There are several factors that influence how annoyed you get with something. Firstly, since the event itself is usually quite benign, its frequency or duration is an important factor2. People talking for five minutes next to your desk when you are trying to work may be tolerated, but if they do it for an hour, you may feel differently. A second factor is your perceived control over the event. Often, just the idea of being able to stop something already makes it less bothering. For example, if a roommate plays loud music, you may be already less annoyed just knowing that if you asked her, she would instantly put it down. Thirdly, it can depend on your mood or tolerance level how quickly you get annoyed. This can be conceptualized as a tolerance level that goes up or down. Any event that goes over this line, will cause annoyance.
In the comic, Murphy is trying to get some work done, but is disturbed by his colleague’s music. He asks him to use headphones, but soon it becomes clear this only makes matters worse.